You may specify the variant by GAPPS_VARIANT. The default is pico.
You still need to add .repo/local_manifests/opengapps.xml to enable it.
Refer to https://github.com/opengapps/aosp_build for more details.
$(call inherit-product,frameworks/native/build/tablet-10in-xhdpi-2048-dalvik-heap.mk)
# Get GMS
-$(call inherit-product-if-exists,vendor/google/products/gms.mk)
+GAPPS_VARIANT ?= pico
+$(call inherit-product-if-exists,$(if $(wildcard vendor/google/products/gms.mk),vendor/google/products/gms.mk,vendor/opengapps/build/opengapps-packages.mk))
# Get native bridge settings
$(call inherit-product-if-exists,$(LOCAL_PATH)/nativebridge/nativebridge.mk)